YMD
jd2ymd(JD jd)
{
YMD ymd;
double j;
double x;
int y, m, d;
j = jdGetDay(jd);
j2gcal(&y, &m, &d, j);
ymdSetYear(ymd, y);
ymdSetMonth(ymd, m);
ymdSetDay(ymd, (double)d);
x = (j - floor(j));
/*
** we do this next step because the rounding of j in j2gcal()
** either credits or debits us with 12 hours
*/
if (x < 0.5) {
x += 0.5;
} else {
x -= 0.5;
}
ymdIncDay(ymd, x);
/* pick up the hours, minutes, and seconds */
ymd.hms = jd.hms;
return(ymd);
}
int main(){
JD jd;
double t =0.0;
#define L 2
double j[L][4] = {
{2451545.0, 10.0, 0.0, 0.0},
{2433142.678, 10.123, -10.345, 1.04}
};
for(int i=0; i < L; i++){
jdSetDay(jd, j[i][0]);
jdSetHours(jd, j[i][1]);
jdSetMinutes(jd, j[i][2]);
jdSetSeconds(jd, j[i][3]);
printf("%16.8f %8.4f %8.4f %8.4f\n", jdGetDay(jd), jdGetHours(jd),
jdGetMinutes(jd), jdGetSeconds(jd));
t = jd2y(jd);
printf("%16.8f\n\n", t);
}
return 0;
}
